#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <set>
#include <bitset>
#include <utility>
using namespace std;

#define mm(a, n) memset(a, n, sizeof a)
#define mk(a, b) make_pair(a, b)

const double eps = 1e-6;
const int INF = 0x3f3f3f3f;

typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef pair<int, LL> PIL;

inline void quickread() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
}

const int N = 1e4 + 10;

int n;
string num[N];

bool cmp(const string & s1, const string & s2) {
    return s1 + s2 < s2 + s1;
}

inline void solution() {
    cin >> n;
    for (int i = 0; i < n; i ++ ) cin >> num[i];

    sort(num, num + n, cmp);

    string res = "";
    for (int i = 0; i < n; i ++ ) 
        res += num[i];

    int k = 0;
    while (k + 1 < res.size() && res[k] == '0') k ++ ;
    cout << res.substr(k) << endl;
    return ;
    
}

int main() {
    freopen("input.txt", "r", stdin);
    quickread();
    solution();
    return 0;
}